If anything can be said to have "gone viral" in the pre-digital age, then it was Orson Welles's 1938 radio adaptation of The War of the Worlds. Telling HG Wells's story of an alien invasion by means of realistic news bulletins, Welles created genuine panic.

But what would happen if the same stunt were pulled using the awesome, scare-spreading capabilities of the internet?

More than 430,000 people have clicked on a YouTube clip purporting to be from an Italian news bulletin reporting the imminent arrival of extraterrestrials.

The snippet is from a film, L'ultimo terrestre (The Last Earthling), to be shown at the Venice film festival later this month.

But the newsreader is a real TV journalist, Maria Cuffaro, who presents prime-time bulletins on the state-owned RAI network.

Rather less comfortingly, Cuffaro says there is no intention of interrupting essential services such as gas and electricity "for the moment".

Still poker-faced, she goes on to tell viewers that the Vatican will soon make public previously secret passages in the Bible that forecast the arrival of extraterrestrials. And she quotes a priest as calling on the faithful to consult a fictitious encyclical, Adventus Marzianus.

RAI asked people to heed Cuffaro's advice and not be panicked into hoarding — a call that may have been needed given the uncanny realism of the video extract: a broken sentence at the start shows the arrival of creatures from outer space is not the lead item, but has been pushed down the running order by injuries to two of the players in the Italian national football squad.